Definition of suck-boy:
(v) :
(transitive) To use the mouth and lips to pull in (a liquid, especially milk from the breast).
(v) :
(intransitive) To perform such an action; to feed from a breast or teat.
(v) :
(transitive) To put the mouth or lips to (a breast, a mother etc.) to draw in milk.
(v) :
(transitive) To work the lips and tongue on (an object) to extract moisture or nourishment; to absorb (something) in the mouth.
(n) :
(uncountable) The ability to suck; suction.
(n) :
An instance of drawing something into one's mouth by inhaling.